Herbicidal composition

ABSTRACT

A herbicidal composition which comprises as an active ingredient a herbicidally effective amount of the combination of (a) 2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetrahydro-1H-isoindole-1,3(2H-dione and (b) a compound of the formula: ##STR1## wherein R 1  is any one of the formulas: ##STR2## wherein R 2  is a C 1  -C 4  alkyl group, and an inert carrier or diluent. The composition shows a synergistic herbicidal potency.

The present invention relates to a herbicidal composition. Moreparticularly, it relates to a herbicidal composition comprising as theactive ingredients (a)2-[7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl]-4,5,6,7-tetrahydro-1H-isoindole-1,3(2H)-dione(hereinafter referred to as "Compound (I)") of the formula: ##STR3## and(b) a compound of the formula: ##STR4## wherein R₁ is any one of theformulas: ##STR5## wherein R₂ is a C₁ -C₄ alkyl group (hereinafterreferred to as "Compound (II)").

A great number of chemicals having a herbicidal activity have been usedto exterminate or control the undersired vegetation of weeds inagricultural and nonagricultural fields. Since, however, weeds arediversified in kinds and their growth extends over a long period oftime, the herbicidal effects of conventional herbicidal agents are quiterestricted in general. Consequently, the appearance of any herbicidalagent which exerts a strong herbicidal activity against a wide varietyof weeds without any material phytotoxicity to crop plants has beenhighly demanded.

No-till cultivation has recently been developed for saving labor,extending the cultivation period, preventing a soil decrease, etc.Because of this reason, there is a demand for herbicides which exert adistinct herbicidal activity in foliar treatment, maintain a prolongedherbicidal efficacy in soil treatment and show a prominent selectivityto crop plants.

As the result of an extensive study, it has now been found that theassociated use of Compound (I) and Compound (II) as the activeingredients produces a highly enhanced herbicidal activity against awide variety of weeds in agricultural and non-agricultural fields. Incomparison with the sole use of each of the active ingredients,enhancement of the herbicidal potency on such associated use isremarkable so that the active ingredients may be applied in a smallerdosages. Further, the weed-control spectrum is greatly enlarged. Thus, aclear and definite synergistic effect is observed in said associateduse. They can be used with high safety for no-till cultivation of cropplants such as soybean and peanut crops.

The herbicidal composition of the invention can exterminate or control avariety of weeds, of which examples are broad-leaved weeds such as wildbuckwheat (Polygonum convolvulus), pale smartweed (Polygonumlapathifolium), curly dock (Rumex crispus), common purslane (Portulacaoleracea), common chickweed (Stellaria media), common lambsquarters(Chenopodium album), slender amaranth (Amaranthus gracilis), redrootpigweed (Amaranthus retroflexus), radish (Raphanus sativus), wildmustard (Sinapis arvensis), shepherdspurse (Capsella bursa-pastoris),hemp sesbania (Sesbania exaltata), sicklepod (Cassia obtusifolia),velvetleaf (Abutilon theophrasti), prickly sida (Sida spinosa), fieldpancy (Viola arvensis), catchweed bedstraw (Galium aparine), ivyleafmorningglory (Ipomoea hederacea), tall morningglory (Ipomoea purpurea),field bindweed (Convolvulus arvensis), purple deadnettle (Lamiumpurpureum), henbit (Lamium amplexicaure), jimsonweed (Daturastramonium), black nightshade (Solanum nigrum), persian speedwell(Veronica persica), common cocklebur (Xanthium strumarium), commonsunflower (Helianthus annuus), scentless chamomile (Matricariaperforata), corn marigold (Chrysanthemum segetum) and Japanese mugwort(Artemisia princeps); Gramineae weeds such as Japanese millet(Echinochloa frumentacea), barnyardgrass (Echinochloa crus-galli), greenfoxtail (Setaria viridis), large crabgrass (Digitaria sanguinalis),annual bluegrass (Poa annua), meadow foxtail (Alopecurus pratensis),blackgrass (Alopecurus myosuroides), water foxtail (Alopeculusgeniculatus), oats (Avena sativa), wild oats (Avena fatua), johnsongrass(Sorghum halepense), quackgrass (Agropyron repens), downy brome (Bromustectorum) and bermudagrass (Cynodon dactylon); Commelinaceae weeds suchas asiatic dayflower (Commelina communis); Cyperaceae weeds such as riceflatsedge (Cyperus iria) and purple nutsedge (Cyperus rotundus), etc.

Compound (I) is known to exert a herbicidal activity (U.S. Pat. No.4,640,707). Compound (II) is also known as a herbicide (The PesticideManual, Ed. by The British Crop Protection Council, Vol. 8, pages 379,404 and 453; Farm Chemicals Handbook 1986, C225). Some examples ofCompound (II) are shown in Table 1 below.

                                      TABLE 1                                     __________________________________________________________________________    Chemical structure              Remarks                                       __________________________________________________________________________     ##STR6##                       Fluazifopbutyl                                 ##STR7##                       Haloxyfopmethyl                                ##STR8##                       Fenoxapropethyl                                ##STR9##                       Quizalofopethyl                               __________________________________________________________________________

However, the associated use of Compound (I) and Compound (II) has neverbeen attempted, and the production of any synergistic effect on suchassociated use has never been expected.

The proportion of Compound (I) and Compound (II) as the activeingredients in the composition of the invention may vary within aconsiderably, broad range. Generally, however, Compound (II) may be usedin an amount of about 0.4 to 50 parts by weight, preferably of about 0.4to 20 parts by weight, to one part by weight of Compound (I).

In addition to the above active ingredients, the composition may containa solid or liquid carrier or diluent. Any surface active or auxiliaryagent may be also incorporated therein. Thus, the composition may beformulated in any conventional preparation form such as wettable powderor suspension. The total content of the active ingredients in thecomposition may be from about 1 to 90% by weight, preferably from about2 to 80% by weight.

As the solid carrier or diluent, there may be used kaolin clay,attapulgite clay, bentonite, terra alba, pyrophyllite, talc,diatomaceous earth, calcite, walnut-shell powder, urea, ammoniumsulfate, synthetic hydrated silica, etc. Examples of the liquid carrieror diluent are water, etc.

The surface active agent used for dispersion or spreading may be any ofthe anionic and nonionic type of agents. Examples of the surface activeagent include alkylsulfates, alkylarylsulfonates,dialkylsulfosuccinates, phosphates of polyoxyethylenealkylaryl ethers,polyoxyethylene alkyl ethers, polyoxyethylene alkylaryl ethers,polyoxyethylene polyoxypropylene block copolymers, sorbitan fatty acidesters, polyoxyethylene sorbitan fatty acid esters, etc. Examples of theauxiliary agent include ligninsulfonates, sodium alginate, polyvinylalcohol, gum arabic, CMC (carboxymethyl cellulose), PAP (isopropyl acidphosphate), etc.

Practical embodiments for preparation of the composition areillustratively shown in the following Formulation Examples whereinpart(s) are by weight.

Formulation Example 1

Fifteen parts of Compound (I), 30 parts of fluazifop-butyl, 3 parts ofcalcium ligninsulfonate, 2 parts of sodium laurylsulfate and 50 parts ofsynthetic hydrated silica are mixed well while being powdered to obtaina wettable powder.

Formulation Example 2

One part of Compound (I), 1 part of quizalofopethyl, 0.5 part ofpolyoxyethylene sorbitan monooleate, 0.5 part of CMC and 97 parts ofwater are mixed and pulverized until the particle size becomes less than5 microns to obtain a suspension.

Formulation Example 3

7.27 parts of Compound (I), 72.73 parts of fluazifop-butyl, 3 parts ofcalcium ligninsulfonate, 2 parts of sodium laurylsulfate and 15 parts ofsynthetic hydrated silica are mixed well while being powdered to obtaina wettable powder.

Formulation Example 4

Fifteen parts of Compound (I), 30 parts of haloxyfop-methyl, 3 parts ofcalcium ligninsulfonate, 2 parts of sodium laurylsulfate and 50 parts ofsynthetic hydrated silica are mixed well while being powdered to obtaina wettable powder.

Formulation Example 5

Three parts of Compound (I), 60 parts of fenoxaprop-ethyl, 3 parts ofcalcium ligninsulfonate, 2 parts of sodium laurylsulfate and 32 parts ofsynthetic hydrated silica are mixed well while being powdered to obtaina wettable powder.

A composition comprising Compound (I) and Compound (II) thus formulatedis useful for post-emergence control of undesired weeds by foliartreatment, for example. Further, in order to improve the herbicidalactivity, the composition may be used together with other herbicides.Besides, it may be used in combination with insecticides, acaricides,nematocides, fungicides, plant growth regulators, etc. Due to the broadherbicidal spectrum, it may be also effective as the herbicide to beapplied in plowed fields, non-plowed fields, borders for rice fields,orchards, pasture lands, lawns, forests, non-agricultural fields, etc.

The dosage of the active ingredients may vary depending on the mixingratio, the formulation used, the crop and weed species, the prevailingweather conditions, the soil involved, etc. In general, however, thetotal amount of Compound (I) and Compound (II) is favored to be within arange of about 50 to 2000 grams per hectare. More specifically, thetotal amount of the active ingredients therein may be within a range ofabout 100 to 1000 grams per hectare.

In case of the composition being formulated into a wettable powder or asuspension, it is normally diluted with water and applied at a volume ofabout 100 to 1000 liters per hectare to the area where extermination ofweeds is desired. The dilution may further contain, in addition to theabove mentioned surface active agent, any spreading or auxiliary agentsuch as polyoxyethylene resin acid esters, ligninsulfonates, abieticacid, dinaphthylmethanedisulfonates, paraffin, petroleum oil and thelike.

The practical herbicidal activity of the composition of the inventionwill be explained in further detail with reference to the following TestExamples wherein the growth controlling percentage (%) was determined byweighing the aerial parts of the test plants (fresh weight) and makingcalculation according to the following equation: ##EQU1##

Test Example 1

Seeds of meadow foxtail were sowed in Wagner's pots (inner diameter, 16cm; height, 19 cm) filled with upland field soil, and cultivated for 40days outdoors. A designated amount of the composition in the form of awettable powder formulated according to Formulation Example 1 wasdiluted with water containing a spreading agent and sprayed over thefoliage of the test plants at a spray volume of 500 liters per hectareby the aid of a small hand sprayer. The spreading agent as used was asurfactant containing dialkylsulfosuccinate and added to water in anamount of 0.5% (v/v) in regard to the total dilution. At the time of thetreatment, meadow foxtail had about 25 cm in height. The plants werecultivated outdoors for 21 days after the treatment, and the growthcontrolling percentage was observed. The results are shown in Tables 2to 3.

                  TABLE 2                                                         ______________________________________                                                 Growth controlling percentage of                                              meadow foxtail (%)                                                            Compound (I) (g/ha)                                                           0   6.3    12.5   25    50  100  400 800                             ______________________________________                                        Fluazifop-                                                                             0      0     0    3    9     19  32  81  94                          butyl    50    14    24   47   58     67  85                                  (g/ha)  100    31    41   64   80     89  93                                          200    49    71   87   97    100 100                                          400    79    96   100  100   100 100                                  800     91     100   100  100  100   100                                      ______________________________________                                    

                  TABLE 3                                                         ______________________________________                                                 Growth controlling percentage of                                              meadow foxtail (%)                                                            Compound (I) (g/ha)                                                           0   6.3    12.5   25    50  100  400 800                             ______________________________________                                        Haloxyfop-                                                                             0      0     0    4    7    19   38  86  95                          methyl   25    12    14   39   42    51   65                                  (g/ha)   50    26    41   68   75    87   93                                          100    42    64   78   94    99  100                                          200    75    90   100  100   100 100                                          400    92    100  100  100   100                                      ______________________________________                                    

Test Example 2

Sandy plowed fields were turned up and, after border building, plottedinto blocks of 3 m² each. Seeds of meadow foxtail, downy brome,catchweed bedstraw, persian speedwell and common chickweed were sowedtherein, followed by cultivation for 130 days. The plants grown inheights of about 5 to 30 cm were treated with the test compositionprepared in the same manner as in Test Example 1. The plants werecultivated for 21 days after the treatment, and the growth controllingactivity was observed. The results are shown in Table 4.

                                      TABLE 4                                     __________________________________________________________________________                 Growth controlling percentage (%)                                Active  Dosage                                                                             Meadow                                                                             Downy                                                                             Catchweed                                                                           Persian                                                                             Common                                      ingredient                                                                            (g/ha)                                                                             foxtail                                                                            brome                                                                             bedstraw                                                                            speedwell                                                                           chickweed                                   __________________________________________________________________________    Compound (I)                                                                           30   6    3   82    96    92                                                  60  22   18   94   100    97                                                 360  70   52  100   100   100                                         Fluazifop-butyl                                                                       150  47   51   0     0     0                                                  300  78   81   0     0     0                                                  360  88   94   0     0     0                                          Compound (I) +                                                                        30 + 150                                                                           96   94   98   100    97                                         Fluazifop-butyl                                                                       60 + 150                                                                           100  100 100   100   100                                                 30 + 300                                                                           100  100 100   100   100                                                 60 + 300                                                                           100  100 100   100   100                                         __________________________________________________________________________

Test Example 3

Winter wheats conventionally grown by stripe seeding cultivation inlevel row were harvested, and seeds of soybean were sowed between thewheat stubbles by drill seeding. Three days thereafter and beforegermination of soybean, a designated amount of the composition in theform of a wettable powder formulated according to Formulation Example 1was diluted with water containing a spreading agent (80% ofparaffin-based petroleum oil and 20% of polyoxyethylene sorbitan fattyacid ester and sorbitan fatty acid ester) in an amount of 1% (v/v) andsprayed uniformly over the top of the weeds remaining in the wheat fieldand having heights of about 20 to 50 cm by the aid of a small handsprayer. After 40 days of the treatment, the growth controllingpercentage on the weeds and the phytotoxicity to soybean were observed.The results are shown in Table 5 wherein the results with a mixture ofglyphosate and metribuzin were also given for control.

                                      TABLE 5                                     __________________________________________________________________________                          Growth controlling percentage (%)                                             Against weeds existed                                                                    Against weeds germed                                               before treatment                                                                         after treatment                              Active  Dosage Phytotoxicity                                                                        Water                                                                              Pale  Barnyard                                                                           Slender                                                                            Pale                               ingredient                                                                            (g/ha) to soybean                                                                           foxtail                                                                            smartweed                                                                           grass                                                                              amaranth                                                                           smartweed                          __________________________________________________________________________    Compound (I) +                                                                        30 + 360                                                                             0      100  100   95   100  100                                Fluazifop-butyl                                                                       50 + 360                                                                             0      100  100   100  100  100                                Glyphosate +                                                                          1000 + 400                                                                           3      100  100   87   100  100                                Metribuzin                                                                    __________________________________________________________________________

The results in Test Example 1 were analyzed according to the isobole(i.e. equivalent efficacy line) method [Vol. 3, Herbicides, pages109-111 (1981) in "Noyaku Jikkenho" (Methods in Pesticide Science)edited by Junichi Fukami et al., Soft Science Inc., Tokyo]based on theTammes's method [Tammes, P.M.L.: Neth. J. Plant Path., 70, 73-80(1964)]. Namely, several combinations of the compositions havingdifferent mixing ratios of Compound (I) and Compound (II) but exertingthe same level of growth control effect, for example, 90% growthcontrol, were plotted in a graph so as to readily determine asynergistic effect, an arithmetic effect or a competitive effect. Incase of exhibiting the synergistic effect, the equivalent efficacy lineas plotted is shown below the arithmetic efficacy line.

Explaining further in detail with reference to the accompanyingdrawings, FIG. 1 wherein the ordinate indicates the dosage offluazifop-butyl and the abscissa indicates the dosage of Compound (I)show that the equivalent efficacy line (i.e. solid line) of 90% growthcontrol of meadow foxtail is located below the arithmetic efficacy line(i.e. dotted line), from which it is understood that the associated useof Compound (I) and fluazifop-butyl in a certain mixing ratio produces asynergistic effect; and FIG. 2 wherein the ordinate indicates the dosageof haloxytopmethyl and the abscissa indicates the dosage of Compound (I)shows that the equivalent efficacy line (i.e. solid line) of 90% growthcontrol of meadow foxtail is located below the arithmetic efficacy line(i.e. dotted line), from which it is understood that the associated useof Compound (I) and haloxyfop-methyl in a certain mixing ratio producesa synergistic effect.

What is claimed is:
 1. A herbicidal composition which comprises as anactive ingredient a herbicidally effective amount of the combination of(a)2-(7-fluoro-3,4-dihydro-3-oxo-4-(2-propynyl)-2H-1,4-benzoxazin-6-yl)-4,5,6,7-tetrahydro--1H-isoindole-1,3(2H)-dione and (b) a compound of the formula: ##STR10## wherein R₁ is any oneof the formulas: ##STR11## wherein R₂ is a C₁ -C₄ alkyl group, and aninert carrier or diluent, and wherein the weight proportion of thecomponents (a) and (b) is from 1:0.4 to 1:50.
 2. The compositionaccording to claim 1, wherein the weight proportion of the components(a) and (b) is from 1:0.4 to 1:20.
 3. A method for controlling weedswhich comprises applying a herbicidally effective amount of thecomposition
 4. The method according to claim 3, wherein the total amountof the components (a) and (b) is from 100 to 1000 grams per hectare. 5.The composition according to claim 1, wherein R₁ is ##STR12##
 6. Thecomposition according to claim 1, wherein R₁ is ##STR13##
 7. Thecomposition according to claim 5, wherein the weight proportion of thecomponents (a) and (b) is from 1:0.4 to 1:20.
 8. The compositionaccording to claim 6, wherein the weight proportion of the components(a) and (b) is from 1:0.4 to 1:20.
 9. The method according to claim 3,wherein R₁ is ##STR14##
 10. The method according to claim 3, wherein R₁is ##STR15##
 11. The method according to claim 9, wherein the weightproportion of the components (a) and (b) is from 1:0.4 to 1:20.
 12. Themethod according to claim 10, wherein the weight proportion of thecomponents (a) and (b) is from 1:0.4 to 1.20.